Correlation of Gene‐specific Damage with Cisplatin between Human Adenocarcinoma Cells and Peripheral Blood Mononuclear Cells Analyzed by Polymerase Chain Reaction‐stop Assay

We investigated gene‐specific damage in adenocarcinoma cells, obtained from pleural effusions of 9 primary lung cancer patients, induced by incubation with cisplation for 3 h in vitro. The 2.7 kb fragment of the hypoxanthine phosphoribosyltransferase (HPRT) gene was amplified by the polymerase chain reaction (PCR) to quantify the DNA damage. A 7‐fold difference in the extent of gene‐specific damage among the patients was observed. Mononuclear cells (MNC) were obtained from freshly isolated blood from the same patients before they received chemotherapy. These cells were also incubated with cisplatin in vitro, and PCR amplification of the HPRT gene was carried out. A 4‐fold variation of DNA damage among the patients was observed. Moreover, there was a linear correlation between the extents of the DNA damage in the tumor cells and MNCs (R(2)=0.676, P=0.0016). These results suggest that the PCR‐stop assay could be used to detect interindividual variations in the extent of gene‐specific damage in both tumor cells and MNC from the same patients induced by cisplatin treatment. In conclusion, MNC could be used to analyze cisplatin‐induced gene‐specific damage in cancer patients whose tumor cells are inaccessible.